The present invention relates to slide projectors in general and, more particularly, to a slide projection system for projecting slides that are stored in space, co-planar relation in a light transmitting, planar holder without removing the slides from the holder during previewing and/or projection of the slide.
The ubiquitous colored slide or "transparency" film is used by both amateur and professional photographers to record various events. The resulting positive slides can be viewed individually in a hand viewer or projected by a slide projector onto a screen. Although positive-to-positive prints can be made from the color transparencies the usual viewing method is by projection. Various systems have been developed over the years for storing and projecting such slides.
Initially, the first simple projectors received the slides upside down, and one-by-one. Subsequent improvements led to a cross-feed system in which the slides were loaded from either side of the projector. Automatic cross-feeds for stacked slides was the next development in the projection art. Later on, magazines or cassette feeds were employed to prove a slide storage medium which operated in conjunction with the projector. Representative examples of various types of slide viewers, projectors and storage units are shown in the following U.S. Pat. Nos.: 2,660,920; 2,779,116; 2,821,037; 2,968,882; 3,462,210; 3,524,703; 3,609,026; and 3,696,538.
At the present time slides are stored in round trays, for either horizontal or vertical use in the projector, in rectangular slide trays and in "cubes". In each case, the slides are stored upside down in the storage tray. Recently, some complicated optical systems have been used to rotate and preview single slides a certain distance ahead of the slide to be projected. In each one of these storage mediums, the slide has to be removed from its holder in order to preview or otherwise inspect the slide. Unless the projectionist knows the contents of his slide tray throughly, he must remove the slide for inspection with a concomitant increase in the probability of deleterious fingerprints and general wear and tear on the slide. Given these mechanical impediments to slide viewing, it is understandable that many people only enjoy their pictures occasionally.
It is accordingly a general object of the present invention to provide a slide projection system in which the slides can be previewed and/or projected without removing the slides from their holder.
It is a specific object of the invention to provide a slide projection system in which the slides can be previewed in their natural orientation and projected to form a naturally oriented image.
It is still another object of the invention to provide a slide projection system with individual and/or group previewing of the slides and random slide selection for projection.
It is a further object of the invention to provide a slide projection system having a slide indexing mechanism that utilizes a cooperative mechanical/electrical relationship between the projection unit and the planar slide holder.
It is a feature of the invention that the projector "feed" is performed with the stored slides in their natural orientation.
It is another feature of the invention that the light transmitting, planar, slide holder can be stored in an album type holder and can be removed from and replaced therein with a minimum of effort.